simplify extractor constants

- single strings for URL patterns
- tuples instead of lists for 'directory_fmt' and 'test'
- single-tuple tests where applicable

gallery_dl/extractor/mangastream.py

@@ -16,12 +16,12 @@ class MangastreamChapterExtractor(ChapterExtractor):
     """Extractor for manga-chapters from mangastream.com"""
     category = "mangastream"
     archive_fmt = "{chapter_id}_{page}"
-    pattern = [(r"(?:https?://)?(?:www\.)?(?:readms\.net|mangastream\.com)/"
-                r"r(?:ead)?/([^/]*/([^/]+)/(\d+))")]
-    test = [
-        ("https://readms.net/r/onepunch_man/087/4874/1", None),
-        ("https://mangastream.com/r/onepunch_man/087/4874/1", None),
-    ]
+    pattern = (r"(?:https?://)?(?:www\.)?(?:readms\.net|mangastream\.com)/"
+               r"r(?:ead)?/([^/]*/([^/]+)/(\d+))")
+    test = (
+        ("https://readms.net/r/onepunch_man/087/4874/1"),
+        ("https://mangastream.com/r/onepunch_man/087/4874/1"),
+    )
     root = "https://readms.net"
 
     def __init__(self, match):